The Role Of DCs In Immune Tolerance Inducted By Anti-CD45RB Antibody

Objective Anti-CD45RB monoclonal antibody has been reported to inhibit proliferation of T cells and immunologic tolerance.The dendritic cells (DCs) play a immune regulation role by interacting with T cells. This experiment has explored anti-CD45RB monoclonal antibody on maturation and functions of DCs during the differentiation of monocytes into mature DCs(mDCs) in vivo and vitro, to clarify the mechanisms of anti-CD45RB monoclonal antibody inducing immune tolerance.Methods The mature dendritic cells(mDCs) from C57BL/6 mice were cultured with rmGM-CSF,IL-4 and LPS for six days.The bone marrow cells treated with varying doses of anti-CD45RB monoclonal antibody in the experiment group.The phenotype, cell cycle and the phagocytic capability of mDCs were detected by flow cytometry. IL-12 level was determined with an ELISA kit.The exosomes (Dex) from DCs were extracted via repeated filter method, the mDCs and mDex after anti-CD45RB monoclonal antibody treatment and those without treatment (Ab-mDCs and Ab-mDex, respectively) were used for the following experiment of mixed lymphocyte reaction.In vivo, the heart from donor Balb/C mouse were transplanted into C57BL/6 mouse received anti-CD45RB monoclonal antibody at a dose of 0.1 mg/times/day in 0,1,3,5,7 days after transplanting, then BM cells obtained from reciptient mice in 0,1,3,5,7 days, and induced to mDCs with rmGM-CSF,IL-4 and LPS in vitro, and to observe the phenotypes and functioning of mDCs and IL-12 level in supernatant were detected by ELISA.Results In vitro,the result indicated that the expression of CD83,CD80,CD86 and I-Abwere inhibited by anti-CD45RB monoclonal antibody in a dose dependent manner, but the expression of CD11c was no differently between experiment and control groups. The antigen phagocytosis of mDCs was higher and the IL-12 level was lower than that of control group. anti-CD45RB monoclonal antibody could inhibit DCs maturation in a dose dependent manner and the effects of Dex in DCs-induced proliferation of T cells were also in a dose dependent manner. In vivo, mDCs form the receptor mice were anti-CD45RB monoclonal antibody treated, the shape and expression of CD1 lc was no differently compared with control group, but the expression of CD83,CD80,CD86 and I-Ab was decreased in a dose dependent manner, the phagocytic activity was increased and IL-12 level was decreased with time, this result was similar with the result of experiment in vitro.Conclusions These findings suggested in the anti-CD45RB monoclonal antibody could profoundly inhibit the maturation and functioning of DCs in vitro and vivo and generate tolerogenic dendritic cells (tDCs) as well as Dex, thus resulting in obvious inhibition on T cell proliferation, immunosuppression and immune tolerance subsequently.